MULTIPLE-INPUT MULTIPLE-OUTPUT SPATIAL MULTIPLEXING SYSTEM WITH DYNAMIC ANTENNA BEAM COMBINATION SELECTION CAPABILITY

• US 20070230639A1
• Filed: 03/06/2007
• Published: 10/04/2007
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: STIRLING-GALLACHER, Richard
• Granted Patent: US 8,369,436 B2
• Time in Patent Office: Days
• US Class Current: 375/347
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/0874 using subgroups of receive antennas
• CPC Class Codes: H04B 7/088 using beam selection
• CPC Class Codes: H04L 27/00 Modulated-carrier systems

Abstract

The present invention generally relates to the field of wireless communication systems. It particularly refers to a spatial diversity transmitter (110) and a spatial diversity receiver (120) in a wireless multiple-input multiple-output (MIMO) spatial multiplexing system as well as a corresponding method for wirelessly transmitting and receiving modulated RF signals via multiple wireless signal propagation paths (P_l) of a multipath fading channel in a way that correlation between the MEMO channel components are reduced and/or the signal to interference plus noise ratio (SINR) is increased which hence result in an improved bit error rate (BER) or packet error rate (PER) performance of said wireless MIMO spatial multiplexing system. On the receiver side, for example, this is achieved by controlling at least one antenna switching and/or combining means (121a′+b′) to select a specific combination of different fixed beam antennas (121a+b) from each receiver-resident antenna array. According to the invention, said selection is based on estimated values of the channel impulse responses (h_l(τ_l, t)) for said signal propagation paths (P_l). An antenna beam selection control means (129) is configured for selecting a specific antenna beam combination so as to maximize the average signal-to-interference-plus-noise ratios ( γ_l) of RF signals (r_l(τ_l, t, φ_l)) received via said multiple wireless signal propagation paths (P_l) and/or to minimize the correlation coefficients (ρ_rl1rl2(t)) indicating the correlations of different pairs of these RF signals (r_l1(τ_l1, t, φ_l1) and r_l2(τ_l2, t, φ_l2)).

Thereby, each fixed beam antenna (121a+b) of the receiver-resident antenna arrays has a distinct radiation pattern with a different beam center and/or beam width in the azimuth and/or elevation plane, wherein a superposition of all these radiation patterns may cover all possible azimuthal (φ) and/or elevational angles of arrival (θ) of an RF signal (s(t)).

For compensating detected multipath fades in the channel amplitude response (|H_l(f, t)|) of at least one signal propagation path (P_l) between the spatial diversity transmitter (110) and the spatial diversity receiver (120), a receiver-resident channel estimation and/or equalization circuitry (124, 128) is applied.

Claims

1. A spatial diversity receiver for wirelessly receiving a modulated RF signal (s(t)), said spatial diversity receiver (120) having at least two antenna arrays, wherein each antenna array comprises at least two fixed beam antennas (121a+b) with distinct radiation patterns,

whereby

combinations of said fixed beam antennas (121a+b) are selectable for wireless receipt of the modulated RF signal (s(t)).

2. The spatial diversity receiver according to claim 1,

whereby

said spatial diversity receiver (120) comprises an antenna beam selection control means (129) adapted for controlling at least one antenna switching and/or combining means (121a′

+b′

) in order to select a specific combination of fixed beam antennas (121a+b) from each antenna array.

3. The spatial diversity receiver according to claim 2,

whereby

the selection of said specific combination of fixed beam antennas (121a+b) is based on estimated values of the channel impulse responses (h_l(τ

_l, t)) of different wireless signal propagation paths (P_l) between a wireless transmitter (110) and said spatial diversity receiver (120).

4. The spatial diversity receiver according to claim 2,

whereby

each antenna array is connected to an antenna switching and/or combining means (121a′

or 121b′

) for selecting specific combinations of said fixed beam antennas (121a or 121b) which is placed in a receiver branch assigned to said antenna array and directly pre-connected to a down-conversion stage (122a or 122b) of said receiver branch.

5. The spatial diversity receiver according to claim 3,

whereby

said antenna beam selection control means (129) is configured for selecting a specific antenna beam combination so as to maximize the average signal-to-interference-plus-noise ratios ( γ

_l) of RF signals (r_l(τ

_l, t, φ

_l)) received via said wireless signal propagation paths (P_l) and/or to minimize the correlation coefficients (ρ

_rl1rl2(t)) of different pairs of the aforementioned RF signals (r_l1(τ

_l1, t, φ

_l1), r_l2(τ

_l2, t, φ

_l2)).

6. The spatial diversity receiver according to claim 1,

whereby

each fixed beam antenna (121a+b) of said antenna arrays has a distinct radiation pattern with a different beam center and/or beam width in the azimuth and/or elevation plane, wherein a superposition of all these radiation patterns covers all possible azimuthal (φ

) and/or elevational angles of arrival (θ

) from which an RF signal (s(t)) is likely to be received.

7. The spatial diversity receiver according to claim 1,

whereby

a channel estimation and/or equalization circuitry (124, 128) for compensating detected multipath fades in the channel amplitude response (|H_l(f, t)|) of at least one wireless signal propagation path (P_l) between a wireless transmitter (110) and the spatial diversity receiver (120).

8. The spatial diversity receiver according to claim 1,

whereby said receiver is adapted to receive said modulated RF signal in a MIMO system.

9. A spatial diversity transmitter for wirelessly transmitting a modulated RF signal (s(t)), said spatial diversity transmitter (110) having at least two antenna arrays, wherein each antenna array comprises at least two fixed beam antennas (107a+b) with distinct radiation patterns,

whereby

combinations of said fixed beam antennas (107a+b) are selectable for wireless transmission of the modulated RF signal (s(t)).

10. The spatial diversity transmitter according to claim 9,

whereby

said spatial diversity transmitter (110) comprises an antenna beam selection control means adapted for controlling at least one antenna switching and/or combining means in order to select a specific combination of fixed beam antennas (107a+b) from each antenna array.

11. The spatial diversity transmitter according to claim 10,

whereby

the selection of said specific combination of fixed beam antennas (107a+b) is based on estimated values of the channel impulse responses (h_l(τ

_l, t)) of different wireless signal propagation paths (P_l) between the spatial diversity transmitter (110) and a wireless receiver (120).

12. The spatial diversity transmitter according to claim 10,

whereby

each antenna array is connected to an antenna switching and/or combining means for selecting specific combinations of said fixed beam antennas (107a or 107b) which is placed in a transmitter branch assigned to said antenna array and directly post-connected to an up-conversion stage (106a or 106b) of said transmitter branch.

13. The spatial diversity transmitter according to claim 11,

whereby

said antenna beam selection control means is configured for selecting a specific antenna beam combination so as to maximize the average signal-to-interference-plus-noise ratios ( γ

_l) of RF signals (r_l(τ

_l, t, φ

_l)) transmitted via said wireless signal propagation paths (P_l) and/or to minimize the correlation coefficients (ρ

_rl1rl2(t)) of different pairs of the aforementioned RF signals (r_l1(τ

_l1, t, φ

_l1), r_l2(τ

_l2, t, φ

_l2)).

14. The spatial diversity transmitter according to claim 9,

whereby

each fixed beam antenna (107a+b) of said antenna arrays has a distinct radiation pattern with a different beam center and/or beam width in the azimuth and/or elevation plane, wherein a superposition of all these radiation patterns covers all possible azimuthal (φ

_d) and/or elevational angles of departure (θ

_d) from which an RF signal (s(t)) is required to be transmitted.

15. The spatial diversity transmitter according to claim 9,

whereby

channel estimation information of at least one signal propagation path (P_l) between the spatial diversity transmitter (110) and a wireless receiver (120) is received from the receiver via a feedback channel, so that the most suitable combination of fixed beam antennas for optimum performance can be selected.

16. The spatial diversity transmitter according to claim 9, whereby said transmitter is adapted to transmit said modulated RF signal in a MIMO system.

20. A software program product being specially configured for performing a method according to claim 15 when being executed by antenna beam selection control means of a spatial diversity transmitter (110) and/or a spatial diversity receiver (120).

17. A method for wirelessly transmitting and receiving a modulated RF signal (s(t)) via multiple wireless signal propagation path (P_l) between a spatial diversity transmitter (110) and a spatial diversity receiver (120), said spatial diversity transmitter (110) having at least two antennas (107a+b) for wirelessly transmitting said modulated RF signal (s(t)) to the spatial diversity receiver (120) and the spatial diversity receiver (120) having at least two antenna arrays, wherein each antenna array comprises a number (N_A) of fixed beam antennas (121a+b) with distinct radiation patterns, said method comprising the steps of

estimating (S2) sample values of the channel impulse responses (h_l(τ

_l, t)) for each wireless signal propagation path (P_l),

selecting (S5, S6) a specific combination of fixed beam antennas (121a+b) from each antenna array based on estimated values of the channel impulse responses (h_l(τ

_l, t)) for said signal propagation paths (P_l), and

receiving (S6) said RF signal (s(t)) by the selected combination of fixed beam antennas (121a+b).

18. The method according to claim 17,

comprising the steps of

maximizing the average signal-to-interference-plus-noise ratios ( γ

_l) of RF signals (r_l(τ

_l, t, φ

_l)) received via each signal propagation path (P_l) and/or minimizing the correlation coefficient (ρ

_rl1rl2(t)) indicating the correlation between RF signals (r_l1(τ

_l1, t, φ

_l1), r_l2(τ

_l2, t, φ

_l2)) received via different wireless signal propagation paths (P_l1, and P_l2).

19. The method according to claim 17,

whereby said receiver is adapted to receive said modulated RF signal in a MIMO system and said transmitter is adapted to transmit said modulated RF signal in said MIMO system.